Field of the Invention
The present invention relates to a golf club head.
Description of the Related Art
A golf club head includes a hosel portion in which a shaft is inserted. The arrangement of the hosel portion may affect the performance of the golf club head. For example, in some cases, the weight of the hosel portion affects the center of gravity of the golf club head. Japanese Patent Laid-Open No. 2000-5351 discloses a golf club head that reduces the weight of the hosel portion and also provides a reinforcing plate to prevent its strength from lowering.
In addition, for example, the shape of the hosel portion may affect the air resistance of the golf club head. In a club such as a driver with a relatively high head speed, the air resistance of the hosel portion may affect the head speed. Each of Japanese Patent Laid-Open Nos. 2009-279373, 2005-237535, and 2-277474, Japanese Utility Model Laid-Open No. 60-128663, U.S. Pat. Nos. 8,758,157, 8,568,247, 5,674,136, and 5,575,725, and U.S. Patent Application Publication No. 2005/032584 discloses a golf club head that reduces the air resistance by the shape of the hosel portion. To the contrary, U.S. Pat. No. 5,827,132 discloses a golf club head that increases the air resistance by the shape of the hosel portion and prompts face rotation.
When reducing the air resistance, it is effective to reduce the air resistance by the shape of the hosel portion, as in Japanese Patent Laid-Open Nos. 2009-279373, 2005-237535, and 2-277474, Japanese Utility Model Laid-Open No. 60-128663, U.S. Pat. Nos. 8,758,157, 8,568,247, 5,674,136, and 5,575,725, and U.S. Patent Application Publication No. 2005/032584. However, the hosel portion may become bloated, and the weight of the golf club head may increase on the heel side. This readily moves the center of gravity of the golf club head to the heel side, resulting in disadvantage in designing the center of gravity.